1. Field of the Invention
The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of manufacturing a semiconductor device having a resin portion encapsulating wires.
2. Description of the Background Art
Semiconductor packages can be classified in terms of the encapsulation structure into two types, namely hermetically encapsulated packages and non-hermetically encapsulated packages. In particular, transfer molded plastic packages belonging to the non-hermetically encapsulated packages are now dominantly used.
Japanese Patent Laying-Open No. 2002-314003 for example discloses the transfer molded plastic packaging technology. A method of manufacturing a semiconductor device according to the technology includes the following steps.
On a resin frame, an IC chip is secured with a die bonding material. By wire bonding, a bonding pad on the IC chip and a land of the resin frame are electrically connected. A mold is used to perform transfer molding to encapsulate the IC chip in a resin.
In the case where a chip having many and densely arranged bonding pads like a chip of the SoC (System on Chip) type is used, wires connected respectively to the bonding pads are also formed densely. In a transfer molding process, these wires are forced to be shifted to some extent by a fluid mold resin. A problem here is that a certain wire could be forced to be shifted to a particularly greater extent to be brought into contact with the wire located downstream, resulting in electrical short circuit between the wires.